METHICILLIN-RESISTANT Staphylococcus aureus


Thursday, June 2, 2016, 4:45 PM – 4:15 PM

Paul A. Cardenio1, Ronalie B. Rafael1, Yasser C. Cabansag2 and Apolinario V. Yambot2

1 College of Veterinary Science and Medicine, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines

2 Molecular Biology and Biotechnology Laboratory, College of Fisheries, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines


A study was performed to isolate methicillin-resistant Staphylococcus aureus (MRSA) from the nasal vestibule of 50 dogs with skin and respiratory problems from five randomly selected veterinary clinics in Nueva Ecija, Philippines. After conventional laboratory method of isolation of S. aureus, the suspected isolate was verified using multiplex- polymerase chain reaction targeting 16S rRNA, femA , mecA and luk-S genes and was subjected to disk diffusion method. A total of 31 samples grown in Baird-Parker media were suggestive of coagulase-positive staphylococcus while only one was able to grow in the MRSA chromogenic agar. The result was confirmed using M-PCR based on the positive results to 16S rRNA, femA and mecA. However, the isolate was negative to luk-S gene. Antimicrobial susceptibility testing described the isolate as multi-drug resistant due to its resistance pattern to clindamycin, erythromycin and rifampicin. The isolate was intermediate resistant to trimethoprim-sulfamethoxazole, and was susceptible to tetracycline, ciprofloxacin and gentamicin. The mecA gene codes for PBP2a and indicates that the isolate has acquired resistance to penicillin, cephalosphorins, carbapenems and their derivatives. The presence of femA gene is considered to be essential in the expression of the bacterial resistance. The isolate was unlikely to be community-acquired since the isolate was negative for luk-S gene, a marker for highly pathogenic CA-MRSA. Based on the results, it could be categorized as Hospital-Acquired (HA-MRSA) of SCCmec type II or III since these types are large enough to carry additional drug resistance genes that make them more resistant to common drugs used in the treatment of MRSA infections. Other studies conducted proved that MRSA can also be shared between veterinary personnel, owners and companion animals which imply its zoonotic characteristic. Therefore, further scientific study and surveillance of MRSA in the country must be performed to establish the probable transmission between animals and human.

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